Carburetor



Oct. 13, 1953 A. H. WINKLER GARBURETOR Filed Nov. 19, 1949 2 Sheets-Sheet l ATTORNEY 5 A. H. WINKLER 2,655,359

CARBURETOR Fileq Nov. 19, 1949 2 Sheets-Sheet 2 IN V EN TOR.

i LBEET H. WIN/(LEE ATTOENEY Patented Oct. 13, 1953 UNITED STATES PATENT OFFICE.

dix Aviation Corporation, corporation of Delaware South Bend, Ind., a

Application November 19, 1949, Serial No. 128,350

4 Claims.

The present invention relates to carburetors for internal combustion engines, and more particularly to a fuel inlet control mechanism for float type carburetors.

The type of carburetor forming the basis of the present invention is designed primarily for aircraft and tank engines and contains two float chambers disposed on opposite sides of the carburetor induction passage, a fuel discharge jet adapted to receive fuel directly from only one of said chambers, a fuel inlet .valve, and a float in each chamber rigidly connected to one another for controlling said fuel inlet valve. The carburetor is usually so mounted on the engine that the float chambers are located to the front and rear of the induction passage with the chamber containing the discharge jet to the rear to facilitate the flow of fuel to said jet while the plane or tank is climbing. With this arrangement, however, when the plane is in a dive or the tank is moving down a substantial grade, the fuel level rises in the front chamber and lowers in the rear chamber, causing the floats to rise and move the fuel valve toward closed position in an amount disproportionate to the quantity of fuel in the two chambers, decreasing further the fuel level in said rear chamber. If this condition prevails for any length of time, the quantity of fuel in the rear float chamber may become insufficient to supply engine requirements. It is, therefore, the principal object of the present invention to provide a carburetor of the type described above wherein the fuel supply to the main discharge jet is not appreciably affected by variations in normal operating positions or attitudes of the vehicle on which the carburetor is mounted. Another object is to provide a relatively simple float mechanism for controlling the fuel inlet valve of a carburetor which is not materially affected in its operation by substantial off-vertical positions of the carburetor. Further objects and advantages will become apparent from the following description and accompanying drawings wherein:

Figure 1 is a vertical cross-sectional view through a carburetor embodying my invention;

Figure 2 is a horizontal cross-sectional view through the carburetor taken on line 2-2 of Figure 1; and

Figure 3 is a vertical cross-sectional view through the carburetor float chamber taken on line 3-3 of Figure 2.

Referring more specifically to the drawings, and to Figure l in particular, numeral l designates the main body of a duplex downdraft carburetor of the type referred to hereinbefore, I2

the front float chamber, l4 the rear float chamber, l6 and I8 floats disposed respectively in said chambers. 20 an air intake housing, and 22 and 24 covers for float chambers l2 and I 4, respectively. The two float chambers are connected by a passageway 25 near the bottom of the chambers and by passageways 26 and 21 along each side between the induction passages and the main body walls. For convenience of description throughout the specification and in the appended claims, float chamber I2 and float chamber M will be referred to as front and rear float chambers, respectively, even though in some installations, particularly on tank installations, the carburetor may be so arranged that the two float chambers are actually in the same position relative to the front and rear ends of the vehicle. Even in this lateral arrangement, the invention has specific application, particularly as the vehicle rolls from side to side, as for example when a tank is traversing rough terrain.

A conventional mechanically actuated accelerating pump 28 disposed in the central member 29 of the main body between the float chambers is connected to float chamber l2 through inlet passage 30 and check valve 32 and to the induction passages 34 and 34a through passage 38 and check valve 40, and is adapted to be actuated by the throttle valve actuating mechanism 42 through a linkage 44 (partially shown in Figure 3) connected to the upper end of the pump piston assembly 46. Each induction passage 34 and 34a contains a main discharge jet 48 and 48a, respectively, connected to the rear float chamber l4 near the bottom thereof by fuel well 49, passages 50 and 50a and metering jets 52 and 52a. A power enrichment jet 54 disposed in the lower portion of the rear float chamber I4 is connected to the main discharge jets by conduit 58 and is controlled by a valve 58 operated by a vacuum actuated piston 60, depending rod 62 and spring 64, said piston being assembled in cylinder 66 which is connected by a conduit 68 with the induction passages on the engine side of the throttle valves.

The floats l6 and I! of float chambers l2 and I4, respectively, are hollow metallic members securely mounted on a rigid lever which is pivoted on pivot pins 82 and 84 threaded into the wall of the carburetor body It). The lever 80 is provided with a projection 88 for engaging and actuating a valve member 08 mounted in a sleeve 90 and adapted to control the fuel flow into the float chambers through an inlet orifice 92 which is located along one side of the carburetor adjacent the rear float chamber. In order that the fuel in the rear float chamber will be maintained at a level sufllcient to supply the requirements of the engine when the plane or tank is descending,- particularly under power, float IS in the front float chamber is made substantially smaller than float I8 in the rear float chamber so that the float assembly will not urge the fuel inlet valve appreciably nearer closed position during descent, when the fuel level stands high in the front float chamber, than at any other time. As is indicated in the drawings, float I6 is positioned on the lever 80 so that the volumetric displacement of float I6 above the normal fuel level is less than the volumetric displacement of float I8 below the normal fuel level. With this arrangement, when the fuel in the front float chamber reaches a predetermined level during descent, float I6 becomes completely submerged in the fuel and consequently becomes completely ineffective to regulate the fuel inlet valve in response to further increases in the quantity of fuel in the float chambers. Further control of the fuel inlet valve is transferred to float I8 so that said valve is thereafter regulated entirely by float I8 in response to changes in the fuel level in the rear float chamber, from which the fuel for the main discharge is supplied, thus permitting the fuel in chamber I4 to rise to an appreciably higher level during descent than would normally be possible if the two floats were of equal size, such as those used heretofore in carburetors of the present type. It is apparent that the size or volumetric displacement of float I6 may be adjusted relative to the volumetric displacement of float I8 to suit requirements of any particular engine installation. The aforementioned carburetor embodying this arrangement assures an adequate supply of fuel for the engine during descent as well as during other off-level operating positions of the engine.

Although only one embodiment and specific application of the invention has been described herein, many modifications and adaptations may be made without departing from the scope of the present invention.

I claim:

1. A carburetor comprising an induction passage, a float chamber on each side of said induction passage, a discharge jet directly connecting one of said chambers with said induction passage, a fuel inlet valve, and a mechanism for controlling said inlet valve including a float in each chamber, the float in the chamber connected directly to the induction passage having a larger volumetric displacement below the normal fuel level than the volumetric displacement of the other float above the normal fuel level.

2. A carburetor comprisingan induction passage, float chambers on opposite sides of said induction passage, only one of which is adapted to supply fuel directly to said induction passage, a fuel inlet valve adapted to discharge into both chambers, and a float in each chamber for controlling said inlet valve, the float in the chamber adapted to supply fuel directly to the induction passage having a larger volumetric displacement below the normal fuel level than the volumetric displacement of the other float above the normal fuel level.

3. A carburetor comprising an induction passage, a main discharge Jet, a pair of float chambers oppositely disposedin relation to said induction passage, only one of which is adapted to supply tlie principal portion of the fuel directly to the main discharge let, a fuel inlet valve, and a float in each chamber for controlling said inlet valve, the float in the chamber adapted to supply the principal portion of the fuel to the main discharge jet having a larger volumetric displacement below the normal fuel level than the volumetric displacement of the other float above the normal fuel level.

4. In a carburetor, an induction passage, float chambers on opposite sides of said induction passage, a discharge jet connecting one of said chambers with said induction passage, a fuel inlet valve, a float in each chamber for controlling said inlet valve, and a pivoted lever positioning said floats at substantially equal distances from the axis of the pivot, the float in one of said chambers having a larger volumetric displacement below the normal fuellevel than the volumetric displacement of the other float above the normal fuel level.

ALBERT H. WINKLER.

References Cited in the flle of this patent UNITED STATES PATENTS Number Name Date 1,332,319 Carpenter Mar. 2, 1920 1,743,791 Mock Jan. 14, 1930 1,872,291 Hobbs Aug. 16, 1932 2,092,946 Wolfard Sept. 14,1937 2,212,926 Wirth Aug. 27, 1940 

